Alert archive / South Dakota / Tornado Warnings in 2021

Tornado Warning 9, NWS Sioux Falls, SD

August 28, 2021Lincoln County, South Dakota; Lyon County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Aug 28, 2021, 4:39 PM CDT for Lincoln County, South Dakota; Lyon County, Iowa. It was in force for 36 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 28, 2021, 4:39 PM CDT (21:39 UTC)
Expired: Aug 28, 2021, 5:15 PM CDT
In force: 36 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Observed
Hail: 1.75 in

Counties Lyon County, IA, Lincoln County, SD

The radar

The Sioux Falls radar (KFSD), 31 km from the middle of the area, began a volume at 21:44 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Aug 28, 4:45 PM CDT	FUNNEL CLOUD	2 E Harrisburg, SD	ROTATION NOTICED IN CLOUDS OVERHEAD, AND SURFACE WINDS SEEMED TO BE BLOWING UPWARD.
Aug 28, 4:45 PM CDT	TSTM WND GST 70	2 E Harrisburg, SD	BRANCHES ON COTTONWOOD TREE BLOWN UPWARD AND OFF, LANDING ON ROOF OF HOUSE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 28, 3:57 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 9.7 hours before the alert went out and 228 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 9 J/kg
Mixed-layer CIN: -334 J/kg
Mixed-layer LCL: 1540 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 558 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

Open this sounding in Storm Lab

The text

As transmitted.

799 
WFUS53 KFSD 282139
TORFSD
IAC119-SDC083-282215-
/O.NEW.KFSD.TO.W.0009.210828T2139Z-210828T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
439 PM CDT Sat Aug 28 2021

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Western Lyon County in northwestern Iowa...
  Northeastern Lincoln County in southeastern South Dakota...

* Until 515 PM CDT.
    
* At 439 PM CDT, a tornado producing storm was located south of 
  Harrisburg, or north of Canton, moving east at 55 mph.

  HAZARD...Damaging tornado and golf ball size hail.

  SOURCE...Radar confirmed tornado.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This tornadic storm will be near...
  Larchwood around 450 PM CDT.
  Lester and Alvord around 455 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Rock Rapids.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 4333 9670 4346 9667 4350 9613 4331 9613
TIME...MOT...LOC 2139Z 260DEG 49KT 4338 9664 

TORNADO...OBSERVED
MAX HAIL SIZE...1.75 IN

$$

Kalin

1 follow-up statement

477 
WWUS53 KFSD 282156
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
456 PM CDT Sat Aug 28 2021

SDC083-282206-
/O.CAN.KFSD.TO.W.0009.000000T0000Z-210828T2215Z/
Lincoln SD-
456 PM CDT Sat Aug 28 2021

...THE TORNADO WARNING FOR NORTHEASTERN LINCOLN COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM CDT for
northwestern Iowa...and southeastern South Dakota.

LAT...LON 4333 9652 4336 9653 4339 9652 4340 9654
      4341 9655 4346 9657 4350 9613 4331 9613
TIME...MOT...LOC 2156Z 255DEG 39KT 4343 9641 

$$

IAC119-282215-
/O.CON.KFSD.TO.W.0009.000000T0000Z-210828T2215Z/
Lyon IA-
456 PM CDT Sat Aug 28 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR CENTRAL
LYON COUNTY...
    
At 456 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Larchwood, or 12 miles west of Rock Rapids, moving
east at 45 mph.

HAZARD...Tornado and golf ball size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
  Lester, Alvord and Rock Rapids.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4333 9652 4336 9653 4339 9652 4340 9654
      4341 9655 4346 9657 4350 9613 4331 9613
TIME...MOT...LOC 2156Z 255DEG 39KT 4343 9641 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.75 IN

$$

Kalin

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 3:21 PM CDT	Severe Thunderstorm Warning	FSD	Lake, McCook, Miner, Minnehaha, Moody	24 min
Aug 28, 3:56 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Turner, Yankton	49 min
Aug 28, 4:23 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lincoln, Turner	37 min
Aug 28, 4:23 PM CDT	Tornado Warning	FSD	Lincoln, Turner	37 min
Aug 28, 4:33 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha	42 min
Aug 28, 4:45 PM CDT	Tornado Warning	FSD	Lincoln, Minnehaha	30 min
Aug 28, 5:00 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lincoln, Minnehaha	45 min
Aug 28, 6:14 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Lake, McCook	31 min
Aug 28, 6:15 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha, Moody	45 min
Aug 28, 6:17 PM CDT	Severe Thunderstorm Warning	FSD	Hutchinson, McCook, Turner	43 min
Aug 28, 6:44 PM CDT	Severe Thunderstorm Warning	FSD	Davison, Hanson, Lake, McCook, Miner, Sanborn	46 min
Aug 28, 6:44 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha	46 min
Aug 28, 6:48 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Lake, McCook, Minnehaha	42 min
Aug 28, 6:53 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha	52 min
Aug 28, 5:26 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lyon, Osceola	34 min
Aug 28, 5:29 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lyon, Osceola	31 min
Aug 28, 5:34 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	17 min

Nearby

Tornado Warnings in South Dakota, 2021 Tornado Warnings in Iowa, 2021 Every tornado warning in 2021 Tornadoes in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.